Automatic molding machine



July 7, 1942 L. P. CLARK, JR

AUTOMATIC MOLDI- NG MACHINE Filed June 5, 1938 2 Sheets-Sheet 2v aw J0 l du] nu w a ,M n 7 Cw. M, 7 Il @9 9M 10 ab flo..

' Patented July 7, l19442 unirse sTArs rA'rgENT oFFlcE AUTOMATIC MOLDING MACHINE Lancaster P. Clark, Jr., Falriield, Conn.

Application June 3, 1938, Serial No. 211,478

Claims.

the raw material plastic, pressure, gassing, and.

curing. Upon completion of each molding cycle the product is ejected from the mold, the mold cleaned, and then reloaded with raw material.

It is an object of the present invention to pro-- vide a molding machine having duplex sets of molding dies, one set of which is adapted to be subjected to the operations such as ejecting, cleaning and reloading which occur outside of the press, while the other set is in the press undergoing the operations, such as heating, compressing, gassing and curing, which take place in the press. A further object is to provide such a machine in which the various operations are synchronized and may be accurately controlledfor the purpose of properly molding plastic material under various conditions, it being understood that diierent materials require diierent heating temperatures and curing times, and also that these factors vary to a large extent according to the size and thickness oi the piece being molded.

A further object is to provide such automatic equipment which may be attached to a semiautomatic single die molding press of known type.

A further object is to providev such automatic equipment which is readily adapted to different types of dies, and in this respect it is proposed to provide such equipment which can with slight modification be incorporated either in the ordinary type oi single die press with lower movable platen to produce a machine of the type in which the molded article is ejected fromthe top die of the mold, or in the type having the upper platen movable and in which the molded articlev is ejected from the bottom die.

With the above and other objects in view, em-

bodiments of the invention are shown in the accompanying drawings, and these embodiments will be hereinafter more fully described with reference thereto, and the invention will be nally pointed out in the claims.

In the drawings:

Fig. 1 is a front elevation of an automatic molding machine according to the invention, and of the lower movable platen type, in which the molded articles are adapted to -be ejected from the top side.

Fig. 2 is a plan View thereof.

Fig. 3 is a side elevation.

Fig. 4 is a side elevation of a modified form of the invention incorporated in an upper movable platen type of press, in which the molded articles are adapted to be ejected from the bottom.

Fig. 5 is a side elevation of an automatic control mechanism for synchronous automatic operation of the machine according to the invention.

Similar reference characters indicate corresponding 'parts throughout the several gures of the drawings.

Referring to the drawings and particularly to Figs. 1 to 3 thereof, the molding lower movable platen type of press disclosed therein is of the well known post type consisting of a base Il), containing the hydraulic ram Il carrying. the lower platen l2, the base being provided at its upper end with a projecting flange I3 in which the lower ends of the four corner posts i4 are secured by nuts l5, the platen l2 being cut-out at its corners as at i6 to have sliding engagement with the posts. Upon the upper ends of the posts there is mounted the upper I'lxed platen or head l1 secured by nuts i8, to which the upper die of the mold is secured.

In the normal use of a press of this type for semi-automatic molding the upper die is secured at the under side of the upper platen or head I'l and the lower die is secured to the vertically movable platen l2, the molded articles being ejected from the upper die after the molding operation and with the press open, and the lower die being loaded with raw material by means of a loading board which is normally engaged with the lower die.

According to one embodiment of the present invention a pair of upper dies are provided which are adapted to be automatically moved from side to side and into and out of the press, one die being in the press while the other die is moved to the right, and this latter die being in the press while the iirst die is moved to the left, the molded articles being ejected from the die which is out of the Vpress while the other die is in the press. Upon the lower platen there are provided two lower dies adapted to be moved into and out of the press from front to back, one die being ln the press whileA the other is out of the press Where it is loaded with raw material.

Upon the respective sides of the head l1 there are secured ejector brackets I9 and 2U, the lower surfaces of these brackets constituting a continuatlon of the lower surfaces of the head l1 and upon which continuous lower surfaces there are secured lianged guide rails 2l and 22. The two upper dies 23 and 24 are rigidly secured together by means of rack bars 25 and 26 at each side, these rack bars being provided along a portion of their upper surfaces with rack teeth 25* and 26 respectively, and being provided at their inner surfaces with inwardly extending flanges 21 and 2l respectively, which engage the rails 2| and 22 to thus slidably support the two dies so that they may be moved into and out oi the press and into and out of relation with the respective ejector brackets I9 and 20.

'I'his movement is imparted to the dies by means of gears 29 and 30 mounted upon a shaft 3| iournaled in a bearing portion 32 provided in the ejector bracket 20, this shaft being provided at its outer end with a gear 33 which meshes with a rack 34 secured to the end of the piston rod 3,5 of the hydraulic cylinder 36, which is supported at one end by a bracket 31 secured to the forward side of the head I1 and at its other end b y means of a bracket 38 secured to the ejector bracket I9; This cylinder 36 has connected to it the hydraulic tubes 39 and 40 which are adapted to operate the piston rod in opposite directions, and which extend to a suitable automatic control device designed to synchronize the action of this cylinder with the other hydraulic cylinder actuated parts of the machine, it being understood that the other hydraulic cylinders, hereinafter described, are similarly connected to such automatic control device. Such control devices usually consist of a motor operated shaft upon which there is provided a series of cams, each cam being designed for the particular cylinder and being adjustable to accurately control the operation of such cylinder, these cams controlling the valving of the respective cylinders. Such devices are the well known Bristol and Summit time cycle control systems. In Fig. I have illustrated diagrammatically the essential parts of such automatic control device and which consists of a shaft |65 rotated through reduction gearing |66 from an electric motor |61, this shaft having mounted thereon a series of nine cams |68, |68", |68", |684, |68, |68f, |68g ,|68h and |681, which respectively operate valves l69, |69", |69, |69", |69, |691, |69', |69h and |691. These valves control the valving of the hydraulic fluid to the respective hydraulic cylinders for controlling the synchronous operation of the various parts of the machine, the valve |69* being connected by the tubes 81 and 88 to the hydraulic ram |0 of the movable platen, the valve |69b being connected by the tubes 53 and 54 to the ejector cylinder 4|, the valve |69c being connected by the tubes 55 and 56 to the ejector cylinder 42, the valve |69d being connected by the tubes 39 and 40 to the cylinder 46 for operating the upper mold partcarrier, the valve |69e being connected by the tubes 11 and 18 to the cylinder 44 for controlling the lower mold part carrier, the valve |69f beingI connected to the tubes of the cylinder 19 for operating the feeler plate 83, the valve |69l being connected to the tubes of the cylinder 80 for operating the feeler plate 84, the valve |69h being connected by the tubes |05 and |06 to the operating cylinder |03 of the forwardly disposed loading board |0|, and the valve |69i being connected by the tubes |05 and |06 of the cylinder |03 of the rearward loading board |0| Upon the respective ejector brackets I9 and 20 there are provided vertically disposed hydraulic cylinders 4| and 42 mounted upon bearing portions 43 and 44 formed upon the brackets and in which operate vertically movable piston rods 45 and 46, the lower ends of these rods being disposed respectively in upwardly recessed pocket portions 41 and 4I of the brackets and having secured thereon within these pocket portions ejector plates 49 and Il carrying ejector pins Il and 52, which correspond to the number of articles being molded, and are adapted to enter the upper dies 23 and 24 and cooperate with the ejector means forming part of the molds. The cylinder 4|. is provided with hydraulic tubes 53 and 54 and the cylinder 42 is provided with hydraulic tubes 66 and 58, these being connected to the synchronizing control mechanism above referred to.

It will be understood that when the mold 23 is in the press and the mold 24 is moved to the right as shown in Fig.,l the ejector plate 50 will be moved downwardly to eject the articles from the mold, these articles dropping into a suitable receptacle. In the other position with the mold 24 in the press and the mold 23 moved to the right the ejector plate 49 is operated to remove the articles from the mold 23.

Upon the forward and rearward sides of the vertically movable platen 2, there are respectively secured U-shaped frames 51 and 58, the upper surfaces of the sides of these frames being continuous with the upper surface of the platen and there being flanged guide tracks 59 and 60 secured upon these continuous upper surfaces, these tracks extending continuously from the outer end of the bracket 51 to the outer end of the bracket 58. The two lower mold members 6| and 62 are secured together in spaced relation by rack bars 63 and 64 secured at each of their sides, these rack bars being provided along a portion of their under surface with rack teeth 63 and 64n respectively. The molds are provided at their under sides and adjacent their side edges with angular channels 65 and 66 which are engaged by the guide tracks 59 and 60, so that the two molds are slidably supported and can be moved into and out of the press from the front to the rear, it being understood that when the mold 62 is in the press the mold 6| is moved rearwardly upon the bracket 58.

This movement is imparted to the racks and molds vby means of gears 61 and 68 mounted upon a shaft 69 journaled in a bearing portion 10 provided in the bracket 51, a gear 1| being secured upon the end of this shaft which meshes with a rack 12 secured to the piston rod 13 of a hydraulic cylinder 14, this cylinder being supported upon the bracket 58 by means of bracket supports 15 and 16. Hydraulic tubes 11 and 18 are connected to the cylinder 14 and extend to the synchronizing control device above referred to. Upon the respective ends of the brackets 51 and 58 there are provided vertically disposed hydraulic cylinders 19 and 80 in which piston rods 8| and 82 operate, these piston rods having mounted upon their upper ends feeler plates 83 and 84 carrying a series of feeler fingers 85 and 86. These feeler fingers are designed for the purpose of insuring against any material remaining in the molds after they move out of the press, so that the molds will be absolutely clean before being reloaded. These fingers are designed for the particular mold shapes and upon entering the mold through vertical movement of the piston will remain stationary with respect to the plate if there is no obstruction in the mold such as a piece of the molded material. If there is an obstruction the lingers are designed to become displaced, which displacement closes an electric circuit to produce a signal, and automatically stop the machine, and which signal will cause the attendant of the machine to remove the piece of material remaining in the mold and then restart the machine.

VThis feeler operation takes place as soon as the mold is moved out of the press, the feeler head moving downwardly into engagement with the mold, and then moving upwardly, so as to provide a space between the upper surface of the mold and the feeler plate into-which space the loading board moves automatically as will presently more fully appear, this loading board being disposed at a fixed level which corresponds to the level of the lower mold when the lower mold in the press is inthe raised or closed position, and during which period the plastic material is undergoing the curing process.

It will be seen that the feeler mechanism as well as the feeding mechanism for the lower molds, including the hydraulic cylinder 14, are all carried by the lower movable platen l2. j

Prior to the loading operation the press is gassed, that is, at a predetermined time after the dies are first closed the dies are opened slightly to permit the escape of the gas that forms therein because of the action of the heated mold on the material, the dies then being closed again after this gassing operation and remaining closed for the relatively long curing period, this curing period varying with different materials and with different sizes and thicknesses of articles and being as much as 3 to 5 minutes in some cases. During this curing period the loading mechanism comes into operation. The hydraulic ram,I has connected to it the hydraulic tubes 81 and 88 which are connected to the synchronizing control device above referred to to control the movements of the lower platen at the proper times in the cycle with themovements of the other parts 'of the machine.

The two loading mechanisms are supported upon the ends of a beam 89 secured to the left hand side of the flange I3 of the base l0, these mechanisms being disposed in line with the lower molds 6| and 62 in the respective rearwardly and forwardly moved positions. Inasmuch as these two mechanisms are of identical construction, only one will be described in detail and the same reference characters will be applied to each. mechanism. Each loading mechanism consists of a pair of spaced vertically disposed supporting bracket members 90 and 9| mounted at their lower ends upon one end of the beam 09 and supporting at their upper ends the lower contracted end of the material feeding hopper 92. In spaced relation below the end of the hopper there are secured upon the inner walls of the brackets and 9| guide rails 93 and 04 projecting to the right to a point adjacent the left hand edge of the lower mold and having'their upper surfaces flush with the upper surface of the mold. Upon these rails there is supported the loading board 95, the relation of the guides to the lower die being such that the board will be moved from the guides on the die.

The board is provided with a series of pockets 00 which correspond in position to the cavities of the mold and are of such size as to receive the required measured quantity of material for each article, this material being either in the form of powder or in the form of a pre-formed pellet. The upper surface of the board is flush with the under side of the hopper so that as the board moves into place beneath the hopper the pockets 96 become filled with the material there being provided a suitable scraper 01 within the hopper which engages the upper surface of the board as it moves from beneath the hopper so as to remove the excess material upon the upper surface' of the board.

The pockets96 are in the form of holes which extend entirely through the board and the ma.-

terial is supported during filling of the board and transmission from the hopper to the mold by means of trip slide 98 movable in a slideway 90 in the board and provided with a series of holes |00 which are normally out of register with the holes 06 so that the slide closes the bottom of the holes 96 to thus support the material in the holes.

Upon relative movement of the trip slide the holes |00 register with the holes 96, so that the material in the pockets may drop through, it being understood that this operation occurs when the board is in aligned relation with the mold and the holes ofthe board and in register with the cavities of the mold.

The loading board is provided with an extension board |0| which moves beneath the hopper as the board moves into aligned relation with the die so that the hopper is closed during this operation.

Movement is imparted to the loading board by means of a piston rod |02 operating in a cylinder |03 supported upon a bracket |04 mounted upon the brackets and 9|, this cylinder having hydraulic tubes |05 and |06 connected to it which are connected to the synchronizing control device above referred to. The piston rod |02 is connected to an arm |01 depending from and secured to the outer end of the trip slide 98. The slide is releasably connected to the loading board by means of a pin |08 provided upon the end, of the slide which engages a spring clip |09 secured upon the under side of the loading board, this spring clip having a flared entrance portion H0 and retaining shoulders so designed that the retaining force of the clip is greater than the force required to engage the pin with the clip.

The extension |0| is provided at its end with a pin H2 which is adapted to engage a clip H3 secured upon the wall of the hopper and which is of similar design to the clip |09, being pro` vided with a flared entrance portion llfi and retaining shoulders ||5. As seen in Fig. l the pin |08 is engaged with the clip-|09 so that as the piston rod |02 moves to the right the trip slide carries the loading board with it into position above the lower die. At the point where the holes 96 of the loading board register with the cavities of the mold the pin I2 of the extension |0| has engaged the spring clip H3, and further movement of the loading board to the right is prevented through abutment of the pin l I2 with the inner end of the clip H3. However, the trip slide continues to move to the right through con--4 tinued movement of the piston rod |02, which continued movement releases the p-in |08 from the clip |09, this movement being predetermined so that the holes |00 of the trip slide come intol register with the holes 90 of the loading board, thus releasing the material in the loadingboard which drops into the mold cavities. Upon the return movement of the piston rod the loading board remains fixed through the retaining engagement of the pin H2 with the clip H3 until before the loading board starts its return movement, this return movement of the loading board occurring as soon as the pin |08 is engaged with the clip |00, this continued movement of the trip slide and board to the left releasing the pin ||2 from the clip 3 so that the board returns to the loading position as shown in Fig. 1. In the case of using preformed pellets a suitable magazine feeding mechanism is incorporated in the loading part of the machine.

In Fig. 4 I have illustrated a modification of the invention in which the automatic loading and ejecting mechanism is incorporated in a press of the inverted ram type and in which the articles are ejected from the lower mold. This press is substantially like the press illustrated in Figs. l to 3, except that the ram is inverted, and comprises four posts mounted upon a base |2| and having the fixed lower platen |22 secured thereon by means of a nut |23. Upon the upper ends of the posts there is secured by means of nuts |24 a hydraulic cylinder head |25, in which the hydraulic ram |26 supporting the upper movable platen |21 operates. The cylinder |25 is provided with hydraulic tubes |28 and |29 which are connected to the synchronizing control device. This is similar to that referred to above in connection with the first embodiment.

In the present modification only one upper mold is required, this mold |30 being secured upon the upper movable platen |21. 'Iwo lower molds are provided which are substantially similar in arrangement to the molds of the rst embodiment, these molds |3| and |32 being adapted to move from the front to the rear into and out of relation with the supporting brackets 51 and 58 secured upon the front and rear surfaces of the fixed platen |22. The molds |3| and |32 instead of being rigidly secured to the racks 63 and 64, as in the first embodiment, are pivotally supported upon trunnions |33 and |34 respectively, which trunnions extend through suitable bearing apertures in the racks.

The racks and molds are adapted to slide upon guide rails |35 which are mounted in a similar manner to the rails 59 and 60 of the first embodiment, but which terminate short of the central axis of the dies in the outwardly moved positions, so that they may be rotated into inverted relation for the purpose of ejecting the molded articles therefrom, as will presently more fully appear. Sliding movement is imparted to the racks and moldsby the same mechanism as employed in the first embodiment, namely, the gear 1| and the rack 12 operated by the piston rod 13 of the hydraulic cylinder 14.

Upon one end of each of the trunnions |33 and |34 there are respectively provided pinion gears |36 and |31 which are adapted in the outwardly moved position of the respective molds to move into relation with vertically disposed racks |38 and |39 carried by the piston rods |40 and |4| of hydraulic cylinders |42 and |43 supported upon the brackets 51 and 58 by means of bracket supports |44 and |45. The cylinder |42 is provided with hydraulic tubes |46 and |41 and the cylinder |43 is -provided with hydraulic tubes |48 and |49, these tubes being connected to the synchronizing control device, above referred to. As each die moves to its outward position and its pinion meshes with the vertical rack vertical movement is imparted to the rack to cause the die to be turned into inverted position, and in this position the articles are ejected. In the normal position of each die a pin |50 provided on one side thereof engages a recess |5| in the rack 64 at one side of the trunnion., while in the inverted position this pin engages a recess |62 in the rack at the other 'side of the trunnion.

Instead of the feeler plates, as employed in the first embodiment, there are provided ejector plates |53 and |54 which are disposed in substantially the same relation to the dies. as the feeler plates, these ejector plates having ejector pins |55 and |56 mounted therein, and being supported upon piston rods |51 and |58 movable in piston cylinders |59 and |60 carried upon the brackets 51 and 58. Hydraulic tubes |6| and |62 are .connected to the cylinder |59 and hydraulic tubes |63 and |64 are connected to the cylinder |60, these being connected to the synchronizing control device above referred to.

From the above description it will be obvious that the principles of the invention may be incorporated in other types of molding machines as for instance a press having both upper and lower platens movable.

I have illustrated and described preferred and satisfactory embodiments of the invention, but it will be obvious that changes may be made therein, within the spirit and scope thereof, as defined in the appended claims.

Having thus described my invention what l claim and desire to secure by Letters Patent is:

1. In a molding machine, a press comprising upper and lower platens each having four sides and means for moving one of said platens toward the other, mold guide means disposed in cooperatively aligned relation to one of said platens and projecting in opposite directions from two opposed sides thereof, aV pair of spaced mold parts connected in tandem and movable on said guide means adapted to be successively disposed in and out of aligned relation with the aligned platens in the press by movement of said pair of mold parts in opposite directions whereby one of said mold parts is in alignment with the aligned platens in the press while the other mold part is supported upon said guide means at one side or the other of the press, a second mold guide means disposed in cooperatively aligned relation to said other platen and projecting in opposite directions from two opposed sides thereof and at right angles to the first mentioned guide means, and a pair of spaced mold parts connected in tandem and movable on said second guide means adapted to be successively disposed in and out of aligned relation with the aligned platens in the press by movement of said second pair of mold parts in opposite directions whereby one of said second pair of mold parts is in alignment with the aligned platens in the press while the other of said second pair of mold parts is supported upon said second guide means at one side or the other of the press.

2. In a molding machine, a press comprising upper and lower platens each having four sides and means for moving one of said platens toward the other, mold guide means disposed in cooperatively aligned relation to one of said platens and projecting in opposite directions from two opposed sides thereof, a pair of spaced mold parts connected in tandem and movable on said guide means adapted to be successively disposed in and out of aligned/relation with the aligned platens in the press by movement of said pair of mold parts in opposite directions whereby one of said mold parts is in alignment with the aligned platens in the press while the other mold part is supported upon said guide means at one side or the other of the press, a second mold guide means disposed in cooperatively alignedrelation to said other platen and projecting in opposite directions from two opposed sides thereof and at right angles to the rst mentioned guide means, and a pair of spaced mold parts connected in tandem and movable on said second guide means adapted to be successively disposed in and out of aligned relation with the aligned platens in the press bymovement of said second pair of mold parts in opposite directions whereby one of said second pair of mold parts is in alignment with the aligned platens in the press while the other of said seoond pair of mold parts is supported upon said second guide means at one side or the other ofthe press, and means carried by said movable platen to impart reciprocating movement to said mold parts disposed in relation thereto.

3. In a molding machine, a press comprising a pair of opposed platens, and means for moving one of said platens toward and away from the other, a mold part carried by one of said platens, mold guide means rigidly connected to the other of said platens disposed at right angles to the direction of movement of said movable platen comprising an intermediate portion extending across said other platen and end portions projecting in opposite directions from the opposed sides thereof, a pair of longitudinally spaced mold,

parts carried by and movable on said mold guide means, reciprocating mold part propelling means arranged parallel to said mold guide means for parts carried by and movable on said mold guide means, reciprocating mold part propelling means arranged parallel to said mold guide means for reciprocatory movement at right angles to the direction of movement of said movable platen and connected between said spaced mold parts, whereby said mold parts are .adapted to be successively disposed in and out of aligned relation with said opposed platens by the reciprocatory movement of said propelling means, one oi said pair of mold parts being in alignment with the opposed platens in the press and with said rst mentioned mold part while the other of said pair of mold parts is out of the press in predetermined spaced relation to and in the same plane with said mold part in the press, relative closing and separating movement between said platens adapted to respectively close and separate said aligned mold parts.

5. In a molding machine, a press comprising a pair of opposed platens each having four sides, and means for moving one of said platens toward and away from the other, mold guide means rigidly connected to one of said platens disposed at right angles to the" direction of movement of said movable platen comprising an intermediate reciprocatory movement at right angles to the direction of movement of said movable platen and connected between said spaced mold parts, whereby said mold .parts are adapted to be successively disposed in and out of aligned relation with said opposed platens by the reciprocatory movement of said propelling means, one of said pair of mold parts being in alignment with the opposed platens in the press and with said rst mentioned mold part while the other of said pair of mold parts is out of the press in predetermined spaced relation to and in the same plane with said mold part in the press, relative closing and separating movement between said platensy adapted to respectively close and separate said aligned mold parts.

4. In a molding machine, a press comprising a pair of opposed platens, and means for moving one of said platens toward and away from the other, a mold part carried by said other platen, mold guide means rigidly connected to said movable platen disposed at right angles to the direction of movement ot said movable platen comprising an intermediate portion extending across said movable platen and end portions projecting in opposite directions from the opposed sides thereof, a pair of longitudinally spaced mold portion extending across said platen and end portions projecting in opposite directions from two opposed sides thereof, a pair of longitudinally spaced mold parts carried by and movable on said guide means, reciprocating mold part propelling means arranged parallel to said moldguide means for movement at right angles to the direction of movement of said movable platen, and connected between said spaced mold parts whereby said mold parts are adapted to be successively disposed in and out of aligned relation with said opposed platens by the reciprocating movement of said propelling means, one of saidv mold parts being'in alignment with the aligned platens in the press while the other mold part is supported upon said guide means at one side or the other of the press in predetermined spaced relation to and in the same plane with said mold part in the press, a second mold guide means rigidly connected to said other platen and projecting therefrom in a plane parallel to and spaced from the plane of said first mentioned guide means, and a mold part movable on said second guide means adapted to be successively disposed in and out of aligned relation with the aligned platens in the press by movement of said mold part in opposite directions whereby in one position said mold part is in alignment with the aligned platens in the press While in its other position it is supported upon said second guide at one side of the press.

LANASTER P. CLARK, Jn. 

